Maxim Integrated Secure Microcontroller - Manual (Page 28)

Secure Microcontroller User’s Guide
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= 1, the entire 64kB data memory map is accessed in this way. Clearing EXBS causes the microcontroller
to revert to its selected configuration. In most systems, the EXBS bit is not used.
4.6 DS5001/DS5002 Memory Map Control
Like the DS5000, the DS5001/DS5002 uses SFRs to control the memory map. The memory control
functions include the partition, range, partition mode (PM), expanded bus select (EXBS), peripheral
enable select (PES) and access enable (AE). The partition and range can be selected using the bootstrap
loader discussed in a later section. In addition, the partition can be selected or modified by the application
software by writing to the MCON register. PES is normally used by software and is also controlled by the
MCON register. The range is controlled by a combination of MCON and RPCTL bits. In addition, the
EXBS and AE are controlled using the RTPCL register. MCON and RPCTL are fully documented in the
SFR summary.
Figure 4-6. Peripheral Enables in the Data Memory Map
4.7 Loading and Reloading Program Memory
Soft microcontrollers are programmed through their integral bootstrap loader feature. This loader is also
used to configure the desired options for memory map control. The secure microcontroller uses its low
power lithium-backed circuits to maintain critical settings in the absence of power. For this reason, it is
unnecessary to set the partition, range, etc. after every power-up or reset. Once set, they will remain
unless deliberately modified. Bootstrap loading is discussed in a later section. One of the major
PE4
PE3
PE2
PE1
DATA
MEMORY
PES=1
FFFFh
BFFFh
7FFFh
3FFFh
64kB
0